FreeBSD 7.x has been using version 6 of ZFS, and originally only 8.0 was going to have the newly updated ZFS version: 13.

Last week the core team MFC’d (Merge From Current) the ZFS updates to 7.2, so I cvsup’d and re-build my server’s kernel and world ( with a simple “make buildworld && make buildkernel && make installworld && make installkernel ), rebooted, and now I have the latest ZFS version running:

[root@server ~]> zpool upgrade -v
This system is currently running ZFS pool version 13.

The following versions are supported:

VER  DESCRIPTION
---  --------------------------------------------------------
 1   Initial ZFS version
 2   Ditto blocks (replicated metadata)
 3   Hot spares and double parity RAID-Z
 4   zpool history
 5   Compression using the gzip algorithm
 6   bootfs pool property
 7   Separate intent log devices
 8   Delegated administration
 9   refquota and refreservation properties
 10  Cache devices
 11  Improved scrub performance
 12  Snapshot properties
 13  snapused property
For more information on a particular version, including supported releases, see:

http://www.opensolaris.org/os/community/zfs/version/N

Where 'N' is the version number.